(1) Field of the Invention
The invention relates to the fabrication and the testing of Integrated Circuit (IC) devices, and, more particularly, to an apparatus for a robust Universal Docking System that is used for purposes of docking and undocking of an electronic test head with a semiconductor device handler.
(2) Description of the Prior Art
In the automatic testing of Integrated Circuits (IC) and other electronic devices, special device handlers are used to place the device that is to be tested in position. The electronic testing itself is provided by a large and sophisticated automatic testing system that includes a test head. The test head is required to connect to and dock with the device handler. In such testing systems, the test head is usually very heavy. The reason for this heaviness is that the test head uses high-speed electronic timing signals. The electronic test circuits must therefore be located as close as possible to the device under test. Accordingly, the test head has been densely packaged with electronic circuits in order to achieve high speed testing of state of the art devices.
The state of the art leaves much to be desired in providing a manipulator or positioner that readily and accurately moves the heavy test head in position with respect to the device handler mechanism. The user typically must move the heavy device handler or the heavy positioner in order to provide alignment. When the test head is accurately in position with respect to the device handler, the test head and the device handler are said to be aligned. After the test head and the device handler have been aligned, the fragile test head and the device handler electrical connections can be brought together (that is docked) thereby enabling the transfer of test signals between the test head and the device handler. Prior to docking, the test head and the device handler electrical connections must be precisely aligned to avoid damaging the electrical connectors.
In a typical operational environment that has as function the electrical testing of semiconductor devices, the test head is manually guided to connect delicate electrical pins to the contacting plate of the device handler, without thereby making use of alignment guides. After this operation of guiding the test head has been completed (that is the test head has been positioned in the location where the test head can be connected and docked with the device handler) the test head is locked or kept level by means of a device manipulator. This often presents problems during production testing. For instance, the position of the test head can change as a consequence of which the electrical connections with the device handler are interrupted. Or the device handler vibrates causing intermittent electrical connections with the device test head or even causing damage to the electrical equipment.
Due to the complexity and density of advanced, sophisticated semiconductor devices, the number of connections that must be provided to the semiconductor device during the test operation can be very large resulting in a heavy cable that must be connected to the device under test. This heavy cable provides increased weight and mass that further aggravates the problem of establishing and maintaining firm positioning between the test head and the device handler of the semiconductor device. Special arrangements are typically provided for the heavy interconnect cable, which address problems of being able to position the test head into the desired position without interference by the cable, providing flexibility in positioning of the test head without interference by the heavy cable, avoiding interference of the cable with freedom of movement that must by provided to the operator of the test equipment, keeping the length of the cable at a minimum to avoid negative electrical performance aspects that can be introduced as a consequence of a long electrical path to the device under test, maintaining mechanical stability to the combined and interlocked device handler and the test head thereby negating the need for mechanical counterbalancing arrangements, and the like.
Prior Art methods of positioning the test head with respect to the device handler frequently use lead screws and sliding/rotating mechanisms of various designs that assisted in the positioning of the test head with respect to the device handler. These mechanisms are in addition frequently aided by electrical motors that provided three-dimensional degree of movement in addition to rotational movement of the components of the test assembly. The various motions that are provided in this manner are however difficult to control to the required degree of accuracy leading to potential damage to device or test head pins, pins that are in most cases of a delicate nature and therefore easily damaged. The addition of the indicated components such as electrical motors and the like further require extensive floor space and do therefore not meet the need that positioning apparatus must be of a simple but sturdy design.
Semiconductor device testing can further take place in a clean room environment. Where this ability to perform device testing in a clean room environment is required, this requirement must not add a significant amount of either expense or complexity to device testing components such as device handler, test head and positioning and docking arrangements that are required for the device testing. Usable space within a clean environment usually involves considerable expense in providing this clean room environment, further emphasizing the need for test components that are simple in design and sturdy in their application.
U.S. Pat. No. 5,440,943 (Holt et al.) shows test head manipulator that facilitates docking and docking of the test heads and device handlers.
U.S. Pat. No. 4,893,074 (Holt et al.) and U.S. Pat. No. 5,149,029 (Smith) show other testing systems with test heads and device handlers.
U.S. Pat. No. 5,600,258 (Graham et al.) (inTEST Corporation) shows an automated docking test head and device handler.
The present invention addresses the problem of quickly and reliably positioning and interlocking a Universal Docking system (UDS) handler plate with respect to a UDS test head plate.
The primary objective of the present invention is to provide an apparatus for establishing quick and reliable connections between a semiconductor device handler plate and a semiconductor device test head plate.
Another objective of the present invention is to reduce the negative effect on device yield caused by unreliable interconnection between a device handler plate and a device test head plate.
Yet another objective of the present invention is to reduce the need for device re-testing due to unreliable testing results caused by unreliable device handler plate to device test head plate connections (re-screen downtime reduction).
Yet another objective of the present invention is to reduce the downtime required for changing equipment set-up in semiconductor testing and manufacturing environments.
In accordance with the objectives of the invention a new method and apparatus is provided to quickly and reliably position, connect and dock a handler plate with a test head plate of a Universal Docking System. The handler plate is provided with at least two roller assemblies whereby each roller assembly consists of a main body or block to which four roller bearings or dowel pins are connected whereby the roller bearings protrude from the vertical body of the roller assembly in a horizontal plane. The test head plate is provided with at least two matching (with the roller assemblies of the handler plate) receiver block assemblies to which a sliding block is attached. Each receiving block assembly of the test head plate is provided with a sliding block whereby the sliding blocks are interconnected with a pivoting linkage assembly such that the movements of the sliding blocks (and with that the movements of the receiving blocks) are synchronized with respect to each other. Each sliding block is provided with a cutout that is designed such that a roller bearing (of the roller assembly) can slide through this cutout. After positioning the roller block with respect to the receiver block and engaging (by the sliding block) at least one of the roller bearings of the roller assembly, the sliding block will be (manually) forced in a direction such that the roller bearing (that now slides through the cut-out of the sliding block) will be further inserted into the receiving block. Since the roller assembly is attached to the handler plate and the receiver block is attached to the test head plate, the action of forcing the roller bearing into the receiver block results in forcing the handler plate closer to the test head plate. The pivoting arrangement that is part of the sliding block assembly synchronizes the motions of the sliding blocks such that, for all receiving blocks, the roller bearings will enter the receiving blocks at the same rate resulting in the plane of the handler plate and the plane of the test head plate remaining parallel during the process of bringing the two plates together. After the roller bearings of the roller assemblies have been forced into the receiver blocks, thereby positioning and locking the handler plate with respect to the test head plate, electrical contact between the electrical contacts of the device handler and the electrical contacts of the device test head has been established. The device is now securely positioned for testing.